I did a talk on this in 2018: Most of the talk is on conversions, but I get in to a bit of the performance aspects toward the end

There's also this issue: https://github.com/gradle/gradle/issues/9225

And: https://github.com/gradle/kotlin-dsl-samples/issues/902

as well as this youtrack issue: https://youtrack.jetbrains.com/issue/KT-24668#comment=27-2936027

and especially on very first project init

but since the developers of kotlin or Android Studio are advancing this approach, I will also use it until I notice critically serious impairments in build speed

Luckily configuration cache is coming, and it means that, unless you change a build script, once cached, it will take 0 seconds to compile them, or to run the configuration

(and a small "secret" it uses absolute paths, but if your CI always use the same absolute path for the build you can reuse it from another build)